File Access

[Leeus]

I am trying to open a txt file in a project using the .openfile command within the IO namespace, this works fine but when I try and use it on a file that is being written to it won't let me!! That is understandable but notepad seems to manage it!! Can I do this by opening it in read only mode or something??

[aewarnick]

You shouldn't have a problem. This works

//my own messagebox and own Read File method:
a.MB.ShowDialog(a.Files.ReadText("D:\\test.txt"));

//the Read File method in class a, class Files (my own classes):
/// <summary>
		/// Reads a text file from disk.
		/// </summary>
		public static string ReadText(string path)
		{
			string s="";
			Stream F=new FileStream(path, FileMode.Open, FileAccess.Read);
			if(F.Length> long.MaxValue)
			{
				int onebyte= 0;
				int bytesR= 0;
				byte[]c= new Byte[ulong.MaxValue];

				while(true)
				{
					onebyte= F.ReadByte();
					if(onebyte==-1) {F.Close(); s= Encoding.ASCII.GetString(c, 0, c.Length); return s;}
					c[bytesR]= (byte)onebyte; ++bytesR;
				}
			}
				
			if(F.Length> int.MaxValue)
			{
				int onebyte= 0;
				int bytesR= 0;
				byte[]c= new Byte[F.Length];

				while(true)
				{
					onebyte= F.ReadByte();
					if(onebyte==-1) {F.Close(); s= Encoding.ASCII.GetString(c, 0, c.Length); return s;}
					c[bytesR]= (byte)onebyte; ++bytesR;
				}
			}

			byte[]b=new Byte[F.Length];
			F.Read(b, 0, Convert.ToInt32(F.Length));
			s= Encoding.ASCII.GetString(b);
			F.Close();
			return s;
		}

[PlausiblyDamp]

Notepad opens the file, reads it in and then closes the file straight away - this stops it keeping the file locked.

[Leeus]

The file we are talking about is a 1.3 gig text file, notepad takes an age to open it!

I can't see how to adapt it for my code??

 

txtfilename.Text = txttype.Text & txtdate.Text & ".LOG"
           Dim filelocation As String = "c:\mail\Log\" & txtfilename.Text
           Dim sr As New System.IO.StreamReader(filelocation)

 

And then I have to do a readline to read the text file in, this is within a look until readline = nothing

[aewarnick]

Why would you be using notepad to open the file if you can just use your program?

[Leeus]

Notepad takes ages but opens the file the VB program gives this error!

 

"The process cannot access the file "c:\mail\Log\PT030928.LOG" because it is being used by another process." I have adapted the code as follows but still doesn't work!

 

           Dim sr As New StreamReader(New FileStream(filelocation, FileMode.Open, FileAccess.Read))

[PlausiblyDamp]

have you tried

 

Dim sr As New StreamReader(New FileStream(filelocation, FileMode.Open, FileAccess.Read, FileShare.Read ))

[Leeus]

Just tried that and still same error!

[aewarnick]

Do you get that error only when Notepad is open? If so, close the file and try again. Otherwise reboot and try again.

[Leeus]

No notepad is not open, the only reason I mentioned it was to prove the file could be opened.

 

The file is a log file constantly being written to.

[aewarnick]

I'm stumped...

[Leeus]

Me too!!!

[tuningd]

I don't know it is possible but could you copy the file and open the copied version that is not being written to?

[aewarnick]

Good thought!